The imprints of the Galactic Bar on the Thick Disk with RAVE

Antoja, T.; Monari, G.; Helmi, A.; Bienaymé, O.; Bland-Hawthorn, J.; Famaey, B.; Gibson, B. K.; Grebel, E. K.; Kordopatis, G.; Munari, U.; Navarro, J.; Parker, Q.; Reid, W. A.; Seabroke, G.; Antoja, Teresa; Steinmetz, M.; Zwitter, T.

Abstract

We study the kinematics of a local sample of stars, located within a cylinder of 500 pc radius centered on the Sun, in the RAVE data set. We find clear asymmetries in the v R v∞ velocity distributions of thin and thick disk stars: there are more stars moving radially outward for low azimuthal velocities and more radially inward for high azimuthal velocities. Such asymmetries have been previously reported for the thin disk as being due to the Galactic bar, but this is the first time that the same type of structures are seen in the thick disk. Our findings imply that the velocities of thick-disk stars should no longer be described by Schwarzschilds, multivariate Gaussian or purely axisymmetric distributions. Furthermore, the nature of previously reported substructures in the thick disk needs to be revisited as these could be associated with dynamical resonances rather than to accretion events. It is clear that dynamical models of the Galaxy must fit the 3D velocity distributions of the disks, rather than the projected 1D, if we are to understand the Galaxy fully.

Citation

Antoja, T., Monari, G., Helmi, A., Bienaymé, O., Bland-Hawthorn, J., Famaey, B., Gibson, B. K., Grebel, E. K., Kordopatis, G., Munari, U., Navarro, J., Parker, Q., Reid, W. A., Seabroke, G., Antoja, T., Steinmetz, M., & Zwitter, T. (2015). The imprints of the Galactic Bar on the Thick Disk with RAVE. Astrophysical journal. Letters, 800(2), L32. https://doi.org/10.1088/2041-8205/800/2/l32

• Acceptance Date: Jan 26, 2015
• Online Publication Date: Feb 20, 2015
• Publication Date: Feb 20, 2015
• Deposit Date: Mar 18, 2016
• Publicly Available Date: Mar 18, 2016
• Journal: Astrophysical journal letters
• Print ISSN: 2041-8205
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 800
• Issue: 2
• Pages: L32
• DOI: https://doi.org/10.1088/2041-8205/800/2/l32
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://hull-repository.worktribe.com/output/433882
• Publisher URL: http://iopscience.iop.org/article/10.1088/2041-8205/800/2/L32/meta
• Additional Information: This is the accepted version of an article published in Astrophysical journal letters, 2015, v.800 issue 2.
• Contract Date: Mar 18, 2016